Prospectus Supplement No.12(To Prospectus dated April 23, 2025) INNVENTURE, INC. This prospectus supplement updates, amends and supplements the prospectus dated April 23, 2025 (the “Prospectus”), which forms apart of the Post-Effective Amendment to the Registration Statement on Form S-1 (Registration No. 333-282971) and is being filed toupdate, amend and supplement the information included in the Prospectus with information contained in each of our Current Reportson Form 8-K which were filed with the SEC on January 12, 2026 (the “Current Reports”). Accordingly, we have attached the Current This prospectus supplement is not complete without the Prospectus. This prospectus supplement should be read in conjunction withthe Prospectus, which is to be delivered with this prospectus supplement, and is qualified by reference thereto, except to the extent thatthe information in this prospectus supplement updates or supersedes the information contained in the Prospectus. Please keep this Shares of our common stock, par value $0.0001 per share (our “Common Stock”), are listed on The Nasdaq Stock Market, LLC underthe symbol “INV.” On January 12, 2026, the closing price of our Common Stock was $4.34 per share. Investing in our securities involves risks that are described in the “Risk Factors” section of the Prospectus. Neither the SEC nor any state securities commission has approved or disapproved of the securities to be issued under theProspectus or this prospectus supplement or determined if the Prospectus or this prospectus supplement is truthful or The date of this prospectus supplement is January 13, 2026. Delaware(State or other jurisdiction ofincorporation or organization) 001-42303(Commission File Number) ☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of1933 (17 CFR §230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2 of thischapter). Emerging growth company☒ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition periodfor complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐ Item 8.01 Other Events. Closing of Accelsius Series B Funding with Legrand and Johnson Controls On December 29, 2025 (the “Closing” or “Closing Date”), Accelsius Holdings LLC (“Accelsius”), a subsidiary of Innventure, Inc.(the “Company”), issued and sold to Legrand DPC, LLC, a Delaware limited liability company (“Legrand”), 822,195 units ofAccelsius’ Series B-1 Units (the “Series B-1 Units”) for gross proceeds of approximately $30 million. Additionally, on the ClosingDate, Accelsius issued and sold to Johnson Controls, Inc., a Wisconsin corporation and an existing holder of Series B-1 Units (“JCI”),an additional 274,065 units of the Series B-1 Units for gross proceeds of approximately $10 million. The approximately $40 million ofaggregate gross proceeds to Accelsius from the Closing is in addition to the approximately $25 million of gross proceeds from theissuance and sale of Series B-1 Units to JCI on October 2, 2025, which was previously disclosed in the Current Report on Form 8-K Accelsius will use the proceeds from the sale of the Series B-1 Units, after deducting certain offering expenses, for general companypurposes. The Series B-1 Units are convertible at any time and from time to time into Accelsius’ Class A Common Units by dividingthe Series B-1 Unit’s Issue Price (as defined below) by the Conversion Price (as defined below) in effect at the time of conversion. The“Issue Price” means $36.4877 per unit, subject to appropriate adjustment in the event of any unit dividend, unit split, combination or The Series B-1 Units have not been registered under the Securities Act of 1933, as amended, may not be offered or sold absent Amendment of Accelsius’ Operating Agreement In connection with the Closing, Accelsius amended its limited liability company agreement (“Operating Agreement”) to, among otherthings, include Legrand as a member and expand the size of Accelsius’ board of directors (the “Board”) to eight directors. Theamendment to the Operating Agreement provides that, for so long as Legrand and its affiliates continue to beneficially own anaggregate of at least 50% of the Series B-1 Units purchased by Legrand (subject to appropriate adjustment for any unit splits, unitdividends, combinations, recapitalizations and the like or any conversion), Legrand will be entitled to designate and remove one The approval of the Legrand Director is required with respect to any Preferred Decision (as defined in t




